This invention relates to a method for producing a photographic support material. More particularly, it relates to a method for producing a polyolefin-coated support material for photographic print paper having a formed pattern such as silk-like pattern.
A variety of methods have heretofore been proposed for imparting a silk-like pattern to the surface of a polyolefin-coated paper. Such proposed methods include so-called grain roll process in which an embossed pattern is imparted to the photographic print paper after the treatment of image print has been completed; a method in which embossing is carried out immediately after coating a photographic emulsion on a polyolefin coated paper; another method wherein the mirror surface of a polyolefin coated paper is embossed by means of an embossing machine; and still another method in which the polyolefin surface is embossed by means of an engraved cooling roll during the step of extrusion-coating a polyolefin resin on a base paper.
When embossing is carried out by any of the above methods, non-uniformity, deformation, flaws, etc., of the engraved pattern on the embossing roll are apt to be replicated on the surface of the polyolefin coated paper, resulting in non-uniform surface, speckles on the surface, uneven gloss, etc. Particularly when an engraved form with a regularly repeated pattern such as silk-like pattern is used to emboss photographic print paper which requires relatively shallow embossing in conformity with the nature of its use, there appear on the embossed polyolefin coated paper diagonal streaks due to feed marks which are often produced on the embossing roll during engraving operation, thus resulting in non-uniform silk-like pattern on the embossed surface. Even when an embossing roll with a uniform pattern is used, there appears, in some cases, glariness on the print paper depending on the design of pattern. The above defects much spoil the quality of a photographic print paper. In order to avoid the above problems, it is necessary to engrave the embossing roll with high precision and to select a suitable design of the pattern. These, however, are technically very difficult and result in increased engraving cost. It is also very difficult to eliminate the feed marks in engraving a roll in a pattern of small depths such as a silk-like pattern.
The present inventors have accomplished this invention as a result of extensive studies to produce an embossed polyolefin-coated paper without the aforesaid defects.